This invention relates to a tree saw and, more particularly, to that type of tree saw referred to as a feller buncher.
In the harvesting of trees, i.e., logging, it has been the practice to mount the felling device on the front of a prime mover such a crawler tractor. The felling device is associated with clamping means to grasp the tree during and after the severing of the trunk and, where auxiliary clamping means are provided, the apparatus can "bunch" trees, i.e., clamping an already cut tree or trees while severing another.
Two basic types of severing means have been employed: the shear type and the saw type. The invention is of the latter type and, more particularly, is of the rim saw sub-type. By driving an annular cutting element from the inside rear, it is possible to cut much larger diameter trees with a given diameter rim saw than with a center driven disc saw--where only the radius is useful in penetrating the trunk.
Certain of the commercially-available feller bunchers of the rim saw type employ horizontally movable carriages to force the saw through the trunk. The inventive tree saw embodies a novel arrangement of hydraulic and mechanical features which allows a bi-directional cutting action, that is to say it may cut in either the clockwise or counterclockwise direction. The inventive carriage embodies a novel arrangement of hydraulic cylinders and rails to provide a narrower, more compact tree saw--an essential when felling trees in a densely forested area. In addition, the carriage has a novel bulkhead and open rear to protect the rim saw against damage. The open rear providing easy discharge of chips and snow without buildup.
The inventive rim saw employs a novel chassis as part of the carriage for removably supporting hook-shaped teeth which can be advantageously sharpened in the field, particularly because the teeth have concave cutting edges. Still further, a novel hydraulic system is provided to correlate the operations of saw rotation and feed control.